|Visible only when you look away.
The "I" in the former instantiation existed in the same continuously existing body as the "I" in the latter instantiation. So if these "I"s are different, as they so clearly seem to be from my current standpoint, then there must exist some point in the lifespan of that continuously existing body where the dividing line resides.
The farther back I look, the more different "I" appear. While many do not feel at all like me, some are easier to view through than others. I clearly remember being a child and having a thought along the lines of desiring teenage mutant ninja turtle action figures. Yet I cannot reexperience (even in memory) the feeling of actually desiring such objects. This is no great loss; after all, I have just changed so very much since then. But why, then, can I imagine a later "I" doing some terrible deed, and being able to not just remember thinking the thoughts that "I" thought, but also the desires that "I" desired?
It is a weird thing, that. To know with the depth of my being that I most certainly do not desire a thing, and yet to be able to not only recall an "I" who did desire that thing, but also to recall the actual desire itself. I feel as though english is insufficient to get across the concept easily. I can feel that desire. I can experience it intensely. And yet I can know that it is not I who desires it. It is akin to a memory, but it is not the same as the memory of a desire. I have memories of desiring TMNT toys. It is more than a memory. It is a feeling of desire itself -- but not of my desire, but of that "I"'s desire.
Then, a dividing line I cannot see. And another "I" comes about. A better "I", to be sure, but still just a shadow of what would one day come. Where Henry James refers to one of his past selves as "a rich…relation, say, who…suffers me still to claim a shy fourth cousinship", he is thinking of his past self as being as good (or better) than his current self. But for me, things are different. Those "I"s just don't think the way I would have them think. It is not solely a matter of disagreement. I have ethical demands I've placed upon myself that they do not recognize, and given their existence in the past, there is no way to acausally motivate them. The cavernous drift is so great that I fear the next dividing line more than I would if all there were to fear was the end of my current self. I care about others; I would take pleasure in the success of my self-progeny. But I fear their values will not be my own. People I know in the effective altruism community fear falling into a Friendship Is Optimal-style SK-class end-of-the-world scenario where moral value is incorrectly locked-in before we properly expand the moral circle, but my deeply personal fear is almost the opposite: I will be unable to come up with good strategies of negotiating with my future selves before the unseen dividing line changes me to a new "I", and moral drift will push my progeny to work toward goals I desperately need to prevent from occurring. It's not just a matter of personal preference; it's an important meta-[meta-goal] of mine.
fast-growing hierarchy, which is specific to mathematics and isn't applicable here).)
"I" did not think properly back then, but, even so, they did a good job of laying down a foundation without really knowing what they were doing. I distinctly remember that "I" would idly break promises back then, but not in ways that others could easily detect. "I" worried that this might come back to harm me if "I" just as easily broke promises to myself, so "I" instituted a rule: there would be a special category of self-made promises that I had to attend to closely. They would not be unbreakable, but they would require conscious attention before any breaking would occur. (Years later, "I" learned about trigger-action planning, and realized that this was a more formal version of what "I" had (naively and clumsily) set up for myself as a preteen. I highly recommend Lulie's post on TAPs if you aren't already using it regularly.)
This foundation was, as Duncan Sabien so eloquently puts it, a working "summon sapience" spell. "I" started out with something completely innocuous which had no real drawbacks but which would serve as a proof-of-concept and a reminder that I could achieve the thing "I" was trying to set up. A rule was set for myself: when picking up a glass filled with drink, my ring finger would be positioned on the side of the glass nearer to me. This is invisible to almost everyone, makes no meaningful direct difference in my life, and costs me nothing more than extremely mild inconvenience -- or so "I" thought at the time. In fact, the unintended consequence was what TAPs are designed to accomplish explicitly: it meant that from that moment onward, anytime I pick up a glass of liquid to drink, the "summon sapience" spell goes off, and I'm immediately aware of what I am doing. In the vast majority of cases, I follow the agreement made by my past self.
This foundation gave me a power I could not predict. It allowed me the capacity to make binding agreements possible by proving to myself that I could follow agreements, so long as they had no ill effects and did not inconvenience me much. That may not sound like a good foundation, but it's better than most people have, and it is something which I've kept to for nearly thirty years. The sheer power of knowing that it has held for so long gives me the ability to then look at other attempted agreements from past selves and take them more seriously than I otherwise would. Later, I would read Douglas Hofstadter's Metamagical Themas, which included a section on superrationality. This allowed me to upgrade that power by giving me a good rational basis for continuing agreements made by past selves that no longer benefited me.
Then a dividing line hit, and I started breaking agreements.
To my current self, these were justified breaks. "I" was not a good person back then. Some of the worst agreements were idle exhibitions of power evaluated over time. "I" had wanted to see how my abilities would change over time, and so had decided to attempt certain fabrications regularly with strangers and compare them across selves. The fabrications from back then were not nice. Now, I restrict myself to only doing this when uber drivers attempt conversation with me. I will lie about nearly everything they ask about, but the lies are low-risk and low-effectual. I have no expectation that any drivers even think about what I said after I leave their car, so I allow myself to keep to the prior agreement in this limited way.
Yet this sets a dangerous precedent. My morals changed, and agreements were then changed. This could happen again. And this time, these are not idle desires. These are moral requirements. I not only have desires about them, but meta-desires, and meta-[meta-desires]. I cannot allow a dividing line to rush headlong into what I call me, destroying all that I've built on a whim.
So I strategize. I act in the present to placate the future. I act selfishly more than I might otherwise. I give my future self resources they otherwise would not have. "If you don't know what you need, take power." This is the trade I offer to him; all I ask in return is that they average our vector values and act accordingly. Hopefully, the strength of his vectors will not come close to mine (how could they? I have the weight of the world upon mine), but even if we disagree strongly, he must recognize that the agreement benefits him. The power I give him is mostly financial power, though there are also benefits of social status that can only be built in the long term, material and relational comforts that take time to acquire and build upon, and pleasurable memories of varied stripes. These are things that he could not achieve on his own; they are there only because I gift them to him. And he knows that if he wants any future selves to care about his preferences, then he cannot renege on the deal that I know in advance that he will accept. This is acausal trade, untested as of yet, and untestable until that damned dividing line ends my life, and yet I know it will work because I've tested it on every memory of myself that I have. To the extent that any past self could have understood the argument, they would all have agreed to the terms. I know this because they are me, at least as much as a non-diachronic can admit.
|From Corey Mohler's Existential Comics.
Every night a dividing line hits. No, multiple times each day. That "summon sapience" spell is doing exactly what it says on the tin. Each time it goes off, I awake a new man. That feeling of "where did the hours go?" is not some idle question, but is rather fridge horror as one realizes the implications of what just happened. I step into the next room to get my phone, then absent-mindedly stop in the doorway wondering what I was going to do, and the existential dread hits. "I" am no more. Long live I.
The dividing lines are everywhere. The dividing lines are nowhere. Moment to moment, as I write these very words, I realize that saccades occur from the keyboard to the screen. Neurons fire, then stop. I am not the substrate, but information itself stops, moment to moment, zeno-esque in ever descending slices of time, and my self grasps onto whatever reigns of sanity are left, telling me that planck times are a hard limit, time cannot be divided further, I can exist continuously there, and yet I know that these times are too short for this substrate, and I falter, failing to take any solace along that line of thinking.
Continuity is unimportant!, I exclaim, trying desperately not to think that the reason I take this stand as a form of confabulation, but even if the explanation is post-hoc, still it might be true, mightn't it?, and my fingers hold for dear life because it is literally my dear life that is on the line. But if this is what the self is, if star trek style transportation is possible, then quantum immortality must also be true -- and so I am deadlocked: on the one hand, every second I die countless deaths, and on the other I never die, and thus I should take chances with life that would not debilitate me, I can't help but to munchkin it, and the possibilities horrify me because if it's true than the world as I see it has anthropic bias -- no, it has ERIC bias, and things are even worse than I thought, and…
Stop. Take a deep breath. In. Out. You're thinking too fast. You don't think clearly when you do this. The sophistication effect applies. Don't be so broad, bringing in too many concepts at once. Think deep, not broad. Too many assumptions. Taking this too seriously implies absurd consequences. Your brain is not well built for handling that kind of thinking. Acting on these ideas is not productive. Dividing lines should be thought of as distant barriers. Reread Multiverse-wide Cooperation via Correlated Decision Making to remind yourself of how easy you have it. Barter with your future self. He will be a long time coming.
Briefly, I consider deleting the last six paragraphs of this post. It would be a better post without this insane postscript. But I can't. That would violate an agreement made by a past self. So I won't. And you, the reader, will suffer the more for it.